Yankton Sioux Tribe v. Southern Mo. Waste Management Dist.

The court holds that an 1894 act of Congress ratifying an 1892 sales agreement for unallotted tribal lands in the Yankton Sioux Reservation did not disestablish the exterior boundaries of the reservation established in 1858; thus, federal environmental regulations apply to a proposed solid-waste facility to be built within the reservation's boundaries. The court first holds that Congress did not express an intent to diminish or disestablish the reservation in the 1894 act. Under the rules of statutory construction, a clause in the 1894 act that provided that the 1858 treaty would remain in effect as though the 1892 agreement had not been made suggests that other sections of the act should be read narrowly to minimize any conflict with the 1858 treaty. Thus, although cession language in two provisions of the act could be viewed as describing a transfer of tribal government authority as well as land, thereby changing the 1858 treaty boundaries, the narrower reading is that the 1894 act simply authorized the conveyance of real property. The court next holds that contemporaneous evidence does not show that Congress intended the 1894 act to diminish or disestablish the reservation. Comments on the floor of the House that unallotted lands would be restored to the public domain were made in reference to a group of agreements with one-half dozen tribes and are of less value in evaluating congressional intent about any individual agreement. There is no statement in the reports by the commissioners sent to secure the sale of unallotted lands that clearly indicates that Congress intended to change the Yankton Reservation boundaries or remove tribal sovereignty over opened areas. Moreover, an 1896 statute in which Congress used the term "former" to refer to a number of unspecified reservations but not to the Yankton Reservation suggests that Congress did not intend to diminish the Yankton Reservation.

The court further holds that evidence regarding the reservation's subsequent history does not present surrounding circumstances that are fully consistent with an intent to terminate the reservation and inconsistent with any other purpose. Congress, in various statutes, has repeatedly referred to the Yankton Reservation as ongoing. Although the executive branch has been less consistent in its treatment of the reservation, the United States as amicus in this case argues that the 1892 agreement, as ratified by Congress, did not diminish or disestablish the exterior boundaries of the Yankton Reservation. While South Dakota's government has consistently exercised various forms of governmental authority over the opened land on the reservation, evidence suggests that at least some state employees had been referring to the reservation as if it still existed. Last, the court holds that even if de facto diminishment were possible in spite of the lack of substantial congressional intent in the 1894 act and its legislative history, historical and demographic evidence does not support such a finding. Fifty-three percent of reservation land was allotted to tribal members who composed at least 40 percent of the population in 1900. Although tribal population decreased somewhat after 1900, the Yankton Sioux currently make up a significant portion of the treaty area and their numbers and economic influence are increasing.